Projection display apparatus, display method for same and image display apparatus

ABSTRACT

The present invention provides a technology that enables related portions of multiple pages of images to be displayed simultaneously. A projection display apparatus comprises: an image extraction section that extracts at least a portion of given first image data as an extraction image; an extraction image memory for storing extraction image data representing the extraction image; an image overlay section that generates overlaid image data by superimposing the extraction image on an original image represented by given second image data; a light modulation unit that is driven responsive to the overlaid image data pixel by pixel; and an optical system for projecting onto the screen the overlaid image obtained by the light modulation unit. A projection display apparatus can display related portions of multiple pages of images simultaneously.

This application is a Division of application Ser. No. 09/632,221 filedon Aug. 3, 2000 now U.S. Pat. No. 6,831,661 which is a CON ofPCT/JP99/00467 filed Feb. 3, 1999.

TECHNICAL FIELD

The present invention relates to an image display apparatus, and moreparticularly to a projection display apparatus technology.

BACKGROUND ART

The ability of a projection display apparatus to take input images anddisplay them enlarged on a screen has led to the extensive use forpresentations. In a presentation a commentary accompanies the imagesprojected onto the screen. Generally, multiple pages of presentationimages are used. While each page of presentation images is different,usually a number of the images are interrelated, so it is necessary tocut back and forth between related presentation pages. Therefore, userswant to be able to simultaneously display at least some of multiplepages of interrelated presentation images.

Also, during question and answer sessions or when a short time is neededbefore a new set of images can be displayed, companies like to displaycorporate logos, products and other such images (which will also bereferred to as specific images) instead of presentation images. In theprior art, specific images were supplied to the projection displayapparatus via an image source apparatus such as a computer, videoplayer, TV receiver or the like. Thus, the problem has been that thespecific image data has had to be stored beforehand in the image sourceapparatus connected to the projection display apparatus.

When no images are being input to the projection display apparatus thescreen remains blank. In such situations, in the prior art theprojection display apparatus displays a one-color screen image called ablank image. In this situation too, users have expressed a desire todisplay specific images. However, this has not been possible becausenormal images are not being input from the image source apparatus. Thisproblem is not limited to the projection display apparatus, but is alsoshared by image display apparatus that display images suppliedexternally.

DISCLOSURE OF THE INVENTION

This invention was accomplished to overcome the foregoing problems ofthe prior art. A first object of the invention is to provide atechnology that enables related portions of multiple pages of images tobe displayed simultaneously. A second object is to provide a technologythat enables specific images to be displayed even when the specificimages are not supplied externally.

In accordance with a first aspect of this invention, the above object isattained by a projection display apparatus that comprises: an imageextraction section that extracts at least a portion of given first imagedata as an extraction image; an extraction image memory for storingextraction image data representing the extraction image; an imageoverlay section that generates overlaid image data by superimposing theextraction image on original image represented by given second imagedata; a light modulation unit that is driven responsive to the overlaidimage data pixel by pixel; and an optical system for projecting onto thescreen the overlaid image obtained by the light modulation unit.

Since this projection display apparatus contains a section forextracting at least a portion of a given image, and an image overlaysection for superimposing the extracted image on the original image, itis possible to simultaneously display multiple pages of interrelatedimage portions.

It is preferable that the image extraction section can arbitrarily setthe portion to be extracted from the first image data, since this makesit easier to produce extraction image data for a particular purpose.

It should also be possible for the image overlay section to superimposethe extraction image at a desired position on the original image, sincethat provides more freedom with respect to overlaying extraction images.

It is also preferable that the extraction image memory stores aplurality of extraction image data representing a plurality ofextraction images, and the image overlay section superimposes at leastone selected extraction image at each specified position on the originalimage.

Doing this makes it possible to select an arbitrary extraction imagefrom among a plurality of extraction images, enabling a desiredextraction image to be overlaid on an original image.

It is preferable for the image overlay section used in the projectiondisplay apparatus to be equipped with a synthesizer section thatgenerates the overlaid image data by synthesizing the given second imagedata and the extraction image data read out from the extraction imagememory; and a frame memory for storing the overlaid image data, theframe memory having at least a memory area corresponding to all thepixels of the light modulation unit. In this case, the overlaid imagedata read out of the frame memory is supplied to the light modulationunit.

With this configuration, since image data consisting of the extractionimages superimposed on the original image is written to a frame memory,the overlaid image can be obtained by reading the overlaid image datafrom the frame memory.

Alternatively, It is preferable for the image overlay section used inthe projection display apparatus to be equipped with a frame memory forstoring the given second image data, the frame memory having at least amemory area corresponding to all the pixels of the light modulationunit; and a synthesizer section that generates the overlaid image databy synthesizing the second image data read out from the frame memory andthe extraction image data read out from the extraction image memory,with the overlaid image data synthesized by the synthesizer sectionbeing supplied to the light modulation unit.

This configuration allows the overlaid image data to be obtained in theprojection display apparatus. Thus, this projection display apparatushas the same function and advantage as the preceding apparatus. Comparedto the preceding configuration in which the overlaid image data is readout of the frame memory and displayed, in this configuration theextraction image is superimposed as the image data is being read out ofthe frame memory. Therefore, the time taken from the initial overlaycommand to the display of the overlaid image is shorter.

In another preferred arrangement, the synthesizer section comprises adata selector that selects either one of the second image data and theextraction image data, pixel by pixel, to produce the overlaid imagedata.

With this configuration, since the data selector selects either one ofthe second image data and the extraction image data, an extraction imagecan be superimposed on the original image by substituting extractionimage data for part of the original image data.

It is preferable for the synthesizer section to be equipped with amultiplier section that multiplies the second image data and theextraction image data by respective coefficients on a pixel by pixelbasis; and an adder section that adds the multiplied second image dataand the extraction image data on a pixel by pixel basis.

With this configuration, the coefficients can be used to adjust thedensity ratio between the embellishment image and the original image.

In another preferred configuration, the synthesizer section comprises acoefficient setting section that controls the coefficients in themultiplier section to change a synthesis ratio between the second imagedata and the extraction image data, thereby adjusting a degree oftransparency of the extraction image superimposed on the original image.

Doing this enables the synthesis ratio between the image data and theextraction image data to be altered by controlling the coefficients ofthe multiplier section, making it possible an overlay image in which theportion overlaid by an extraction image is transmitted.

In the above projection display apparatus, also, it is preferable thatthe coefficient setting section changes the coefficients in themultiplier section with time to change the synthesis ratio between thesecond image data and the extraction image data, thereby changing thedegree of transparency of the extraction image superimposed on theoriginal image with time.

Doing this makes it possible to change with time the degree oftransparency of the portion on which an extraction image is overlaid bychanging the coefficients of the multiplier section with time.

A projection display apparatus according to a second aspect of theinvention comprises: a frame memory for storing image data representingan image to be displayed; a image display signal generator forgenerating image display signals based on the image data stored in theframe memory; a electro-optical device for emitting light to form imagesresponsive to the image display signals; a projection optical system forprojecting light emitted by the electro-optical device; an imageextraction section that extracts at least a portion of an extractiontarget image selected arbitrarily from among images given externally asan extraction image; an extraction image memory for storing extractionimage data representing the extraction image; and a specific imagedisplay control section that in a specific display condition displays aspecific image represented by specific image data including theextraction image data stored in the extraction image memory.

With this configuration, at least a part of a selected target image canbe acquired as the extraction image. In a specific display condition,this makes it possible to display specific image that includearbitrarily extracted image, in place of image given to the projectiondisplay apparatus. Thus, desired specific image can be displayed evenwhen specific images are not being supplied from an external source.

In another preferred configuration, the image extraction sectionimplements the steps of: displaying an extraction image setting screenfor setting image extraction conditions comprising at least anextraction area and an extraction magnification factor; displaying anextraction area specifying image used in setting the extraction area onthe extraction target image; when the extraction area is set with theextraction area specifying image, writing into the frame memory selectedextraction image data representing a selected extraction imagecorresponding to the set extraction area; when a display magnificationfactor is set, enlarging or reducing the selected extraction image databased on the magnification factor and writing the enlarged or reducedselected extraction image data into the frame memory; and when a desireddisplay magnification factor is determined, storing the selectedextraction image data enlarged or reduced based on the desired displaymagnification factor in the extraction image memory.

The extraction image setting screen makes it easier to set the targetextraction image area. Also, before a magnification factor isdetermined, it can be checked by displaying the selected extractionimage corresponding to the set extraction area at the selectedmagnification factor concerned.

In another preferred arrangement, the image extraction section displaysa predetermined extraction frame as the extraction area specifyingimage, the predetermined extraction frame having a first black outline,a second black outline inside the first black outline and a white areabetween the first and second black outlines.

This facilitates setting the extraction area by making it easy todistinguish the extraction area on the extraction target image. Whateverthe color of the extraction target image is, black outlines or whiteimage frame can be displayed clearly.

In another preferred arrangement, the extraction image memory stores aplurality of extraction image data representing a plurality ofextraction images; and the specific image display control sectiondisplays a specific image that include at least one extraction imageselected from among the plurality of extraction images in the specificdisplay condition.

A specific image display control section can be used that selects atleast two of the extraction images from among the plurality ofextraction images and displays the selected images in order.

The ability to choose from among a plurality of extraction images meansthat more effective specific image can be used.

In another preferred configuration, the projection display apparatusincludes an operating condition judging section that judges if theprojection display apparatus is in a specific operating condition,wherein the specific image display control section displays the specificimage when the specific operating condition is detected by the operatingcondition judging section.

This configuration can automatically determine when the projectiondisplay apparatus is in a specific operating condition, and displayspecific image that includes extraction image extracted by the imageextraction section.

Specifically, the operating condition judging section is configured todetect as the specific operating condition at least one state selectedfrom a state in which no image signal is being given to the projectiondisplay apparatus, and another state in which the projection displayapparatus is within a prescribed period after startup.

In each of these states, in which the projection display apparatuscannot perform its normal display function, specific image that includeextraction image extracted by the image extraction section can beautomatically displayed.

A projection display apparatus according to a third aspect of theinvention comprises: a frame memory for storing image data representingan image to be displayed; a image display signal generator forgenerating image display signals based on the image data stored in theframe memory; a electro-optical device for emitting light to form imagesresponsive to the image display signals; a projection optical system forprojecting light emitted by the electro-optical device; an operatingcondition judging section that judges if the projection displayapparatus is in a specific operating condition; and a specific imagedisplay control section that displays the specific image represented bythe specific image data when the operating condition judging sectiondetects the specific display condition.

This configuration can automatically determine when the projectiondisplay apparatus is in a specific operating condition, and displayspecific images at such times.

For this, preferably the operating condition judging section detects asthe specific operating condition at least one state selected from astate in which no image signal is being given, and a state in which theprojection display apparatus is within a prescribed period afterstartup.

As described above, in each of these states in which the projectiondisplay apparatus cannot perform its normal display functions, specificimage that include extraction image extracted by the image extractionsection can be automatically displayed.

An image display apparatus according to a fourth aspect of the inventioncomprises: a frame memory for storing image data representing an imageto be displayed; a image display signal generator for generating imagedisplay signals based on the image data stored in the frame memory; aelectro-optical device for emitting light to form images responsive tothe image display signals; an image extraction section that extracts atleast a portion of an extraction target image selected arbitrarily fromamong images given externally as an extraction image; an extractionimage memory for storing extraction image data representing theextraction image; and a specific image display control section that in aspecific display condition displays the specific images represented by aspecific image data including the extraction image data stored in theextraction image memory.

This image display apparatus has the same function and advantage as theprojection display apparatus according to the fourth aspect. In aspecific display condition selected by a user, the image displayapparatus can display specific image that include arbitrarily extractedimage in place of image given to the image display apparatus.

An image display apparatus according to a fifth aspect of the inventioncomprises: a frame memory for storing image data representing an imageto be displayed; a image display signal generator for generating imagedisplay signals based on the image data stored in the frame memory; aelectro-optical device for emitting light to form images responsive tothe image display signals; an operating condition judging section thatjudges if the projection display apparatus is in a specific operatingcondition; and a specific image display control section that displaysthe specific image represented by the specific image data when theoperating condition judging section detects the specific displaycondition.

This image display apparatus has the same function and advantage as theprojection display apparatus according to the third aspect. It canautomatically detect when the image display apparatus is in a specificdisplay condition, and display specific images.

In accordance with a sixth aspect of the invention, a method ofdisplaying images using a projection display apparatus having a lightmodulation unit to display an image based on image data given to theprojection display apparatus by projecting the image on a screen, whichcomprises the steps of: extracting at least a portion of given firstimage data as an extraction image; preparing extraction image datarepresenting the extraction image; generating overlaid image data bysuperimposing the extraction image on an original image represented bygiven second image data; driving light modulation unit responsive to theoverlaid image data pixel by pixel basis; and projecting onto a screenoverlaid images obtained by the light modulation unit.

This display method has the same function and advantage as theprojection display apparatus according to the first aspect, enablingsimultaneous display of related portions of multiple pages of images.

A display method according to a seventh aspect of the inventioncomprises the steps of: extracting at least a portion of a givenextraction target image as an extraction image; preparing extractionimage data representing the extraction image; and in a specific displaycondition, displaying a specific image represented by specific imagedata including the extraction image data.

This display method has the same function and advantage as theprojection display apparatus according to the second aspect, enabling aspecific image to be displayed even when the specific image is not beingsupplied from an external source.

A display method according to an eighth aspect of the inventioncomprises the steps of: judging if the projection display apparatus isin a specific operating condition; when it is judged that there is aspecific operating condition, storing specific image data to a framememory to display a specific image represented by specific image data.

This display method provides the same function and advantage as theprojection display apparatus according to the third aspect, and is ableto automatically determine when the projection display apparatus is in aspecific operating condition, and display specific images at such times.

At least part of the functions of the above-described method, steps andcomponents of the invention can be implemented by a computer programrecorded on computer-readable recording media such as floppy disks,CD-ROMs, opto-magnetic disks, punched cards, bar codes and other suchprinted symbols, internal storage device (including RAM and ROM) andexternal storage device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram for schematically illustrating a firstembodiment of the general configuration of a projection displayapparatus according to a first aspect of the invention.

FIG. 2 is a block diagram for schematically illustrating theconfiguration of a video signal conversion circuit 10.

FIG. 3 is a block diagram showing the configuration of the videoprocessor 34.

FIGS. 4( a)–(d) are diagrams for explaining the frame memory 22,extraction image memory 24 and extraction image bitmap memory 26 used inthis embodiment.

FIG. 5 is a block diagram for schematically illustrating theconfiguration of the extraction image overlay circuit 12.

FIGS. 6( a)–(c) are diagrams for explaining the overlay operation withrespect to image data stored in the frame memory 22 and extraction imagebitmap data BMD1 stored in the extraction image bitmap memory 26.

FIG. 7 is a diagram for explaining the extraction image bitmap data BMD1expanded in the extraction image bitmap memory 26.

FIGS. 8( a)–(c) are diagrams for explaining examples of displays on aprojection screen 104 of images input from a personal computer on whichextraction images have been superimposed.

FIG. 9 is another diagram for explaining the display on a projectionscreen 104 of an image input from a personal computer on which anextraction image has been superimposed.

FIG. 10 is a diagram for explaining the extraction image bitmap memory26 when the extraction image of FIG. 9 is expanded.

FIGS. 11( a) and 11((b) are diagrams for explaining projected imagesoverlaid with transparent extraction images.

FIG. 12 is a block diagram for schematically illustrating the generalconfiguration of a second embodiment of the projection display apparatusaccording to a first aspect of the invention.

FIG. 13 is a block diagram for schematically illustrating theconfiguration of a video signal conversion circuit 60.

FIG. 14 is a block diagram showing a configuration of the videoprocessor 62.

FIG. 15 is a block diagram for schematically illustrating the generalconfiguration of an embodiment of the projection display apparatusaccording to a second aspect of the invention.

FIG. 16 is a block diagram for schematically illustrating theconfiguration of the video signal processing circuit 210.

FIG. 17 is a block diagram showing a configuration of the videoprocessor 234.

FIG. 18 is a diagram illustrating the extraction image memory 224.

FIG. 19 is a diagram for explaining externally input images displayed ona projection screen 104.

FIG. 20 is a diagram for explaining the projection screen display of aspecific image represented by the specific image data SPD1 that includesbackground image data BGD1 and extraction image data CPD1 stored inextraction image memory 224.

FIGS. 21( a)–(c) are diagrams for explaining the display on theprojection screen 104 of sequentially selected extraction imagesrepresented by extraction image data CPD1 (A), CPD1 (B) and CPD1 (C).

FIG. 22 is a diagram to illustrate the procedure for cutting away froman image being input to the projection display apparatus, to a user logoimage.

FIG. 23 is a diagram for explaining the procedure for cutting away froman image being input to the projection display apparatus, to a user logoimage.

FIG. 24 is a diagram for explaining the procedure for cutting away froman image being input to the projection display apparatus, to a user logoimage.

FIG. 25 is a diagram for explaining the procedure for cutting away froman image being input to the projection display apparatus, to a user logoimage.

FIG. 26 is a diagram for explaining the procedure for cutting away froman image being input to the projection display apparatus, to a user logoimage.

FIG. 27 is a diagram for explaining the procedure for cutting away froman image being input to the projection display apparatus, to a user logoimage.

FIG. 28 is a block diagram for schematically illustrating the generalconfiguration of an embodiment of the projection display apparatusaccording to second and third aspects of the invention.

FIG. 29 is a block diagram showing the configuration of the operatingcondition judging section 226.

FIGS. 30( a)–(e) are time charts of the operation of the operatingcondition judging section 226.

BEST MODES OF CARRYING OUT THE INVENTION

A. First Embodiment

Some modes for carrying out the present invention are described below aspreferred embodiments. FIG. 1 is a block diagram for schematicallyillustrating a first embodiment of the general configuration of aprojection display apparatus according to a first aspect of theinvention. The projection display apparatus includes a video signalconversion circuit 10, an extraction image overlay circuit 12, a liquidcrystal display driver circuit 14, a liquid crystal display panel 16, aframe memory 22, an extraction image memory 24, an extraction imagebitmap memory 26, a remote control section 28, a CPU 20, an illuminationoptical system 100 and a projection optical system 102. The video signalconversion circuit 10, extraction image overlay circuit 12, extractionimage memory 24, remote control section 28 and CPU 20 are connected tovia a bus 1. The liquid crystal display driver circuit 14 is alsoconnected to the bus 1, but this is not shown in FIG. 1. The liquidcrystal display panel 16 is uniformly illuminated by the illuminationoptical system 100, and images displayed on the liquid crystal displaypanel 16 are projected onto the projection screen 104 by the projectionoptical system 102. The optical systems 100 and 102 are shown in asimplified fashion.

The video signal conversion circuit 10 is used to perform analog-digitalconversion of analog video signals AV1, write the converted image datainto the frame memory 22 and retrieve image data from the frame memory22. The analog video signal AV1 can be an RGB signal S1 carrying acomputer screen image, or a composite image signal S2 from a videorecorder, TV or the like.

FIG. 2 is a block diagram for schematically illustrating theconfiguration of the video signal conversion circuit 10. The videosignal conversion circuit 10 includes a sync separator 30, an A-Dconversion section 32 and a video processor 34.

When the analog video signal AV1 is a composite image signal S2, thesync separator 230 separates the signal S2 into a sync signal SYNC and acomponent image signal (analog image signals not including a syncsignal) S3. The component image signal S3 is comprised of three colorsignals representing the red, green and blue images. If the analog videosignal AV1 that is received is an RGB signal S1, there is no need to usethe sync separator 230 since there is a separate sync signal input.

The A-D conversion section 232 contains multiple A-D converters forconverting RGB signal S1 or component image signal (RGB signal) S3output by the sync separator 230 to image data DV1 for each colorsignal. The conversion timing of the A-D converters is controlled by adot clock DCLK generated in the video processor 234, using the syncsignal WSYNC.

The video processor 34 is a microprocessor that performs various imageprocessing functions such as controlling the input and output of imagedata to and from the frame memory 22. Image data DV1 from the A-Dconversion section 32 is stored in the frame memory 22 until required.

FIG. 3 is a block diagram showing the configuration of the videoprocessor 34. The video processor 34 includes a write controller 70, aread controller 72 and an image extraction section 74.

When image data is written to, or read from, the frame memory 22, thewrite controller 70 and read controller 72 generate addresses ADD1, ADD2and image data is written to the frame memory 22 in accordance withaddress ADD1 and control signal CTR1 generated by the write controller70, and read out of the frame memory 22 in accordance with address ADD2and control signal CTR2 generated by the read controller 72. Theseaddresses and control signals are based on sync signals WSYNC and RSYNC.

The writing of image data to the frame memory 22 is synchronized by thesync signal WSYNC. The retrieval of image data from the frame memory 22and the downstream processing of the image data DV2 output by the videoprocessor 34 are synchronized by the sync signal RSYNC output by theliquid crystal display driver circuit 14 (FIG. 1) explained below. Thefirst sync signal WSYNC and the second sync signal RSYNC are notmutually synchronized. However, sync signals WSYNC and RSYNC can be usedsynchronized.

When image data that has been written into the frame memory 22 is readout, the image extraction section 74 (FIG. 3) extracts a specifiedportion of the image data. The image extraction section 74 compressesthe extracted image data and writes it to the extraction image memory 24via the bus 1. The extracted image data does not have to be compressedby the image extraction section 74. Also, the data can be reducedinstead of compressed. The operation of specifying the portion of theimage data to be extracted can be done using a remote controller 29.When the extraction portion has been specified by the remote controller29, the CPU 20 outputs an extraction address SADD corresponding to thespecified extraction portion. Based on the extraction address SADD andaddress ADD2 that is output from the read controller 72, the imageextraction section 74 extracts the pixel data of the extraction portion.By doing this, only pixel data corresponding to specified portion can beextracted.

The extraction image memory 24 shown in FIG. 1 is used to store theextraction image data extracted by the image extraction section 74 ofthe video processor 34 (FIG. 3). In this embodiment, the extractionimage data is stored in compressed form in the extraction image memory24 as compressed extraction image data CPD. The data CPD is expandedinto extraction image bitmap data BMD1, which is stored in theextraction image bitmap memory 26. The extracted image data may also bestored in uncompressed form in the memory 26, in which case theextraction image memory 24 is unnecessary.

FIGS. 4( a)–(d) are diagrams for explaining the frame memory 22,extraction image memory 24 and extraction image bitmap memory 26 used inthis embodiment. FIGS. 4 (a) and (d) show the memory space in the framememory 22, FIG. 4 (b) shows the memory space in the extraction imagememory 24, and FIG. 4 (c) shows the memory space in the extraction imagebitmap memory 26.

With reference to FIG. 4 (a), the frame memory 22 contains one frame ofthe input image data (a picture of a flower) in a bitmap format. Thebroken line shows the extraction portion, which is defined by the user,extracted and compressed by the image extraction section 74, and storedin the extraction image memory 24 as compressed extraction image dataCPD.

As shown in FIG. 4 (b), the extraction image memory 24 contains multipletypes of compressed extraction image data CPD and a program forexpanding the compressed extraction image data CPD into a bitmap. Theprogram is stored in the memory 24 starting at memory address 0000.Compressed data A, B and C are stored at starting addresses 0A00, 0B00and 0C00, respectively.

The extraction image bitmap memory 26 shown in FIG. 4 (c) is used tostore extraction image bitmap data BMD1 expanded by the program in theextraction image memory 24, and coordinate data PD showing the overlayposition and extent of the extracted image on the original image data.The extraction image bitmap data BMD1 (FIG. 4( c)) is expanded startingfrom address 0000 of the extraction image bitmap memory 26. Thecoordinate data PD is stored starting at address AAAA, and includes twopoint coordinates (x1, y1), (x2, y2). The first coordinate (x1, y1)denotes the overlay position of the extracted image within the imagedata, and the two coordinates (x1, y1), (x2, y2) denote the overlayextent (meaning the size) of the extraction image.

The frame memory 22 shown in FIG. 4 (d) contains image data (a pictureof a tree) in a bitmap format. The extraction image of FIG. 4 (c) isoverlaid on above image. The coordinates (x1, y1), (x2, y2) shown inFIG. 4 (d) are based on the address 0000 of the frame memory 22 beingfor coordinates (0, 0). The coordinates (x1, y1), (x2, y2) correspond tothe coordinate data PD of FIG. 4 (c), in which point a at the upper leftof the extraction image bitmap data BMD1 corresponds to the coordinates(x1, y1), and point b at the lower right corresponds to the coordinates(x2, y2).

When a user selects one of the multiple extraction images prepared byextracting image data, it is expanded as extraction image bitmap dataBMD1. A user can obtain the coordinate data PD by specifying an overlayposition within the image data, or the position and extent of theoverlay. If just an overlay position is specified, coordinates (x1, y1)are determined, and the coordinate data (x2, y2) is set based uponpredetermined sizes set according to the type of extraction imageconcerned. The size is determined when the extraction image isextracted. When both position and extent of the overlay are specified,coordinates (x1, y1) are set according to the overlay positionspecified, and in accordance with the overlay extent (size) specified,coordinates (x2+Δx, y2+Δy) are substituted for (x2, y2). This enablesthe extraction image to be enlarged or reduced to any desired size.Although in this embodiment the extraction image bitmap data BMD1 andcoordinate data PD are stored in the extraction image bitmap memory 26,they can instead be stored in the extraction image memory 24.

The extraction image overlay circuit 12 (FIG. 1) overlays input imagesand extraction images. Specifically, the extraction image overlaycircuit 12 overlays image data DV2 output by the video signal conversioncircuit 10 and extraction image bitmap data BMD1 expanded in theextraction image bitmap memory 26 (FIG. 4( c)).

FIG. 5 is a block diagram for schematically illustrating theconfiguration of the extraction image overlay circuit 12. The extractionimage overlay circuit 12 includes two multipliers 40 and 42, an adder 44and a coefficient setting section 46. The two multipliers 40 and 42 andthe adder 44 constitute a configuration that is provided for each of thecolors RGB. Image data DV2 output by the video processor 34 is input tothe first multiplier 40, and the extraction image bitmap data BMD1expanded in the extraction image bitmap memory 26 is input to the secondmultiplier 42.

The coefficient setting section 46 is used to set the coefficients k1and k2 of the multipliers 40 and 42. Coefficients k1 and k2 can each beset to a value ranging from 0 to 1, and generally are set at a valuethat sums to 1. The coefficients k1 and k2 are controlled by thecoefficient setting section 46 based on the coordinate data PD (FIG. 4(c)).

The multipliers 40 and 42 are used to multiply each pixel data of inputimage data by a constant factor. In the multiplier 40, the image dataDV2 is converted to signals multiplied by k1. Similarly, extractionimage bitmap data BMD1 is converted to signals multiplied by k2. Theconverted data output as image data DV3 and extraction image bitmap dataBMD2 are input to the adder 44.

The function of the adder 44 is to add the pixel data of two input imagesignals. Thus, in the adder 44 the image data DV3 and the extractionimage bitmap data BMD2 are added and output as overlay image data DDV1.The multipliers 40 and 42, adder 44 and coefficient setting section 46correspond to the synthesizer section in the projection displayapparatus according to the first aspect of this invention,

The overlay image data DDV1 output by the extraction image overlaycircuit 12 is supplied to the liquid crystal display driver circuit 14(FIG. 1). The liquid crystal display driver circuit 14 displays on theliquid crystal display panel 16 the image with the extracted imageoverlay corresponding to the overlay image data DDV1. The imagedisplayed on the liquid crystal display panel 16 is projected onto thescreen 104 by the optical systems 100 and 102. More specifically, thelight incident onto the liquid crystal display panel 16 by theillumination optical system 100 is modulated in accordance with imagedata supplied to the liquid crystal display panel 16, and the lightexiting from the liquid crystal display panel 16 is projected onto theprojection screen 104 by the projection optical system 102. The liquidcrystal display panel 16 corresponds to the light modulation unit in theprojection display apparatus according to the first invention.

The projection display apparatus is controlled by the remote controlsection 28 in accordance with commands from the remote controller 29.The remote control section 28 controls mainly processing related to theextraction images. In accordance with commands received from the remotecontroller 29, this includes specifying the portion of an image to beextracted, selecting the type of extraction image and controlling theoverlay position and extent of the extraction images, and whether theextraction images are displayed or not.

Instead of hardware, the functions of the video signal conversioncircuit 10, extraction image overlay circuit 12 and remote controlsection 28 can be realized by a computer program. The computer programfor realizing the functions of these parts can be provided in a formatrecorded on a computer-readable recording medium such as floppy disk,CD-ROM or the like. The program is read off the recording medium by thecomputer (projection display apparatus) and transferred to an internalstorage device or an external storage device. Alternatively, thecomputer program may be supplied from a program supply apparatus via acommunication route. When realizing the computer functions, a computerprogram stored in an internal storage device is executed by the computerCPU (microprocessor). A computer program recorded on a recording mediumcan also be executed directly by the computer.

As used in this specification, “computer” includes hardware and anoperating system, with the hardware being operated under the control ofthe operating system. If the hardware is operated by an applicationprogram having no need of an operating system, then the hardware itselfwill constitute the computer. The hardware comprises at least amicroprocessor like a CPU and means for reading a program recorded on arecording medium. For this purpose, the computer program includesprogram code for realizing the function of each of the means describedin the foregoing. Some of the functions can be implemented by theoperating system instead of an application program.

The recording media in this invention include floppy disks, CD-ROMdisks, opto-magnetic disks, IC cards, ROM cartridges, punched cards, barcodes and other such printed symbols, internal storage devices(including RAM and ROM) and external storage devices.

FIGS. 6( a)–(c) are diagrams for explaining the overlay operation withrespect to image data stored in the frame memory 22 and extraction imagebitmap data BMD1 stored in the extraction image bitmap memory 26. FIG. 6(a) shows the memory space of the frame memory 22, containing image data(text). FIG. 6 (b) shows the memory space of the extraction image bitmapmemory 26, containing extraction image bitmap data BMD1 (a graph) andcoordinate data PD showing the position and extent of the overlay. The(x1, y1), (x2, y2) of this coordinate data PD in FIG. 6 (b) correspondto the coordinates (x1, y1) and (x2, y2) in FIG. 6 (a). FIG. 6 (c) showsthe overlay image data DDV1 consisting of the original image dataoverlaid with the extraction image bitmap data BMD1.

The overlaying of the extraction image bitmap data BMD1 on the imagedata is effected based on the coordinate data PD. In the extractionimage overlay circuit 12 (FIG. 5), the stream of image data is input tothe first multiplier 40 while the second multiplier 42 receives only theextraction image bitmap data BMD1 for the portion defined by thecoordinates (x1, y1) and (x2, y2), which is the overlay portion. Thetiming of the input of the extraction image bitmap data BMD1 to themultiplier 42 is controlled by the CPU 20 based on the coordinate dataPD. Simultaneously with the input of the extraction image bitmap dataBMD1 to the multiplier 42, the coefficients k1 and k2 of the multipliers40 and 42 are adjusted. When extraction image bitmap data BMD1 is notbeing input to the multiplier 42, the coefficients k1 and k2 of themultipliers 40 and 42 are set to (1, 0). When the extraction imagebitmap data BMD1 is being input to the multiplier 42, the coefficientsk1 and k2 are set to (0, 1). As a result, with respect to pixels not inthe area defined by the coordinate data (x1, y1) and (x2, y2), theoriginal image data (text) shown in FIG. 6 (a) is output by theextraction image overlay circuit 12, while with respect to the pixelswithin the area defined by the coordinates (x1, y1), (x2, y2), theextraction image bitmap data BMD1 shown in FIG. 6 (b) is output by theextraction image overlay circuit 12. In this way, the extraction imagebitmap data BMD1 is superimposed on the image data, forming the overlayimage data DDV1 representing the overlay image shown in FIG. 6 (c).

The extraction images can be generated in the extraction image bitmapmemory 26 to correspond with the overlay position within the image data.FIG. 7 is a diagram for explaining the extraction image bitmap data BMD1expanded in the extraction image bitmap memory 26. A portion of theextraction image bitmap memory 26 corresponding to one frame of imagedata is allocated for developing the extraction image bitmap data BMD1,and the extraction image is expanded at the location defined by thecoordinates (x1, y1), (x2, y2). When the expansion takes place, as shownin FIG. 7, pixel data of the image data and the extraction image bitmapdata BMD1 corresponding to the same position in the image are inputsimultaneously to the respective multipliers 40 and 42. At this time,for areas outside the area defined by the coordinate data PD coordinates(x1, y1) and (x2, y2), the coefficients k1, k2) are set to (1, 0), whileinside the area of the coordinates (x1, y1) and (x2, y2), thecoefficients (k1, k2) are set to (0, 1). In this way, the original imagedata can be overlaid with the extraction image bitmap data BMD1,producing the overlay image data DDV1 representing the extraction imageof FIG. 6 (c).

As described above, when an extraction image is expanded as shown inFIG. 7, one frame of memory capacity is required as the memory area forthe extraction image bitmap data BMD1, but when it is expanded as shownin FIG. 6 (b), a memory capacity that is around the same size as thebitmap expanded extraction image is sufficient, so there is theadvantage that the memory capacity can be small.

FIGS. 8( a)–(c) are diagrams for explaining examples of displays on aprojection screen 104 of images input from a personal computer on whichextraction images have been superimposed. FIG. 8 (a) shows input image(text) overlaid with two extraction images (pictures of tree). FIG. 8(b) shows input image (text) overlaid with two types of extractionimages (pictures of a boat and a tree). FIG. 8 (c) shows the input image(text) overlaid with enlarged extraction image (picture of a boat) shownin FIG. 8 (b).

The extraction images shown in FIG. 8 (a) and (b) are overlaid byspecifying the overlay position within the projection image. In thiscase, the coordinate data PD comprises coordinates (x1, y1) showing thespecified position, and coordinates (x2, y2) defined by thepredetermined size of extraction image. The extraction image shown inFIG. 8 (c) is overlaid by specifying the overlay position and extentwithin the projection image. In this case, the coordinate data PDcomprises the preset coordinates (x1, y1) and the coordinates (x2, y2)corresponding to the specified size.

Also, since the extraction image bitmap data BMD1 includes thecoordinate data PD indicating the overlay position, an extraction imagecan be displayed at any point that is specified, using the remotecontroller 29. The extraction image bitmap data BMD1 and the coordinatedata PD are being continually refreshed in sync with the sync signalRSYNC, so the remote controller 29 can be used to move an extractionimage to any point within the projection image, on a realtime basis.Moreover, multiple extraction images can be displayed, as shown in FIG.8 (b). A command issued by the remote controller 29 and received by theremote control section 28 can be used to execute the program in theextraction image memory 24 to generate the extraction image bitmap dataBMD1.

The shape of the extraction image extracted by the image extractionsection 74 is not limited to the rectangles shown in FIGS. 8( a)–(c).Any shape specified using the remote controller 29 can be extracted froman original image by the image extraction section 74, so the extractionimage can be oval, round, star-shaped, or a shape defined by straightlines.

FIG. 9 is another diagram for explaining the display on a projectionscreen 104 of an image input from a personal computer on which anextraction image has been superimposed. As shown in FIG. 9, an ovalextraction image (picture of boat) is superimposed on the original image(text).

In this embodiment, the coordinate data PD includes two pointcoordinates defining the extraction image overlay position and extent.In the case of FIG. 9, the data is processed so that within the areaspecified by the coordinates, the portion where there is no extractionimage is not overlaid.

FIG. 10 is a diagram for explaining the extraction image bitmap memory26 when the extraction image of FIG. 9 is expanded. In the case of thisextraction image bitmap data BMD1, the shaded portion outside the ovalis not to be overlaid on the input image, so the pixels of that portionare comprised using specified pixel data. The pixels where there is noextraction image are comprised of specified pixel data, for example, allthe bits of the RGB pixel data can be set to 0. In this case, when theextraction image bitmap data BMD1 is input to the coefficient settingsection 46, the coefficient setting section 46 checks the data todetermine whether the pixels contain an extraction image. The system canbe set so that when the input image data relates to pixels where thereis no extraction image, the coefficients (k1, k2) of the multipliers 40and 42 are changed to (1, 0). This makes it possible to ensure that onlythat portion of the extraction image bitmap data BMD1 that contains anextraction image will be overlaid on the original image data. It goeswithout saying that the coordinate data PD can be comprised of numerouspoint coordinates around the portion where the extraction image exists,in which case just the said portion containing the extraction imagecould be overlaid, based just on the coordinate data PD.

In the examples shown in FIGS. 8( a)–(c) and 9, the extraction imagesappear as filled-in images on the original input image. This overlayeffect is obtained by the extraction bitmap data being substituted forpart of the original image. In the extraction image overlay circuit 12(FIG. 5) the multiplier coefficients (k1, k2) are set at (1, 0) forthose portions where no extraction image is overlaid, while thecoefficients (k1, k2) are set at (0, 1) for portions where an extractionimage is overlaid.

Transparent extractions can be applied by changing k1 and k2. Settingboth k1 and k2 to ½, for example, would produce a transparent effect inthe portion where the extraction image is overlaid on the input image.

FIGS. 11( a) and 11(b) are diagrams for explaining projected imagesoverlaid with transparent extracted images. FIG. 11 (a) shows images(graphs 1 and 2) input from a computer. The broken line (graph 2)denotes the area specified as the cutout portion. In FIG. 11 (b), thegraph 2 portion of FIG. 11 (a) has been extracted and overlaid on graph1, which can be seen through graph 2. This shows the type of transparentoverlay effect that can be achieved by setting the coefficients k1, k2of the multipliers 40 and 42 in the extraction image overlay circuit(FIG. 5) to ½.

The overlay images shown in FIGS. 8( a)–(c), 9 and 11(a),(b) wereobtained using the multiplier coefficients k1, k2 set at a fixed valuesuch as 0, 1 and ½. However, k1 and k2 values can be used that changewith time. For example, for portions where an extraction image isoverlaid, the coefficients (k1, k2) can start at (0, 1) and, as timepasses, can be gradually changed thus: (0.1, 0.9), (0.2, 0.8) . . . (1,0). As a result, the extraction image overlay would start out lookingsolid, then would gradually become transparent and finally vanish. Suchoverlay effects can be obtained by changing the coefficients K1 and K2with time. The coefficients are adjusted by the coefficient settingsection 46 based on commands from the CPU 20.

The extraction image overlay circuit 12 and frame memory 22 of thisembodiment correspond to the image overlay section according to thefirst aspect of this invention. Similarly, the extraction image memory24 and extraction image bitmap memory 26 correspond to the extractionimage memory of the first aspect of the invention. One of the memories24 and 26 can be omitted.

B. Second Embodiment

FIG. 12 is a block diagram for schematically illustrating the generalconfiguration of a second embodiment of the projection display apparatusaccording to the first aspect of the invention. The projection displayapparatus includes a video signal conversion circuit 60, a liquidcrystal display driver circuit 14, a liquid crystal display panel 16, aframe memory 22, an extraction image memory 24, a remote control section28, a CPU 20, an illumination optical system 100 and a projectionoptical system 102. The video signal conversion circuit 60, extractionimage memory 24, remote control section 28 and CPU 20 are connected viaa bus 1. The liquid crystal display driver circuit 14 is also connectedto the bus 1, but the connection is not shown in FIG. 12.

The projection display apparatus of this second embodiment does not havethe extraction image overlay circuit 12 or the extraction image bitmapmemory 26 possessed by the first embodiment. In this embodiment, thevideo signal conversion circuit 60 is used to overlay extraction imageson the original image. Extraction image bitmap data BMD1 is stored inthe extraction image memory 24. Thus, the video signal conversioncircuit 60 and frame memory 22 correspond to the image overlay sectionof the first aspect of the invention. In this embodiment, only theextraction image memory 24 corresponds to the extraction image memory ofthe first aspect of the invention

FIG. 13 is a block diagram for schematically illustrating theconfiguration of the video signal conversion circuit 60. The videosignal conversion circuit 60 includes a sync separator 30, an A-Dconversion section 32 and a video processor 62. The sync separator 30and A-D conversion section 32 have the same functions as the firstembodiment, so further explanation thereof will be omitted.

The video processor 62 is a microprocessor that performs overlayprocessing of the input image data and extraction image bitmap data, andcontrols the input and output of overlay image data to and from theframe memory 22.

The image data DV1 output by the A-D conversion section 32 and theextraction image bitmap data BMD1 expanded in the extraction imagememory 24 are input to the video processor 62. In the video processor 62the overlay image data is produced by selecting the image data DV1 andthe extraction image bitmap data BMD1, and written into the frame memory22. A data selector in the video processor 62 is used for selection ofthe image data DV1 and extraction image bitmap data BMD1.

FIG. 14 is a block diagram showing the configuration of the videoprocessor 62. The video processor 62 includes a write controller 70, aread controller 72, an image extraction section 74 and a data selector76.

When image data DV1 is input to the video processor 62, the imageextraction section 74 (FIG. 14) extracts the specified portion of theimage data DV1, compresses the data and stores it in the extractionimage memory 24 via the bus 1. The extraction image data does not haveto be compressed, and it can be reduced instead. The remote controller29 can be used to specify the portion of the image data to be extracted.When the extraction portion has been specified, the CPU 20 outputs asampling signal SMP corresponding to the extraction portion. Based onthe sampling signal SMP, the image extraction section 74 extracts thepixel data of the specified portion. In this way, it is possible toextract just the data relating to the pixels of the specified area.

Image data DV1 and extraction image bitmap data BMD1 expanded in theextraction image memory 24 are input to the data selector 76 (FIG. 14),along with a selection signal SEL. There is a data selector 76 for eachof the RGB colors. The selection of the image data DV1 and extractionimage bitmap data BMD1 is done on a pixel data by pixel data basis andis controlled by means of the selection signal SEL. Thus, based on theselection signal SEL, the data selector 76 selects pixel data either oneof the image data DV1 and the extraction image bitmap data BMD1 andwrites the data into the frame memory 22. This data written into theframe memory 22 forms the overlay image data comprised of the originalimage overlaid with the extraction image. The selection signal SEL isgenerated by the CPU 20 according to the coordinate data PD.

In this embodiment the overlay images seem filled in on the originalimage. This corresponds to when, in the first embodiment, thecoefficients (k1, k2) of the multipliers 40 and 42 of extraction imageoverlay circuit 12 (FIG. 5) are set at (0, 1) with respect to theextraction image overlay portion.

When extraction image bitmap data BMD1 is expanded as shown in FIG. 6(b), only the extraction image bitmap data BMD1 for the area defined bythe coordinate data PD coordinates (x1, y1) and (x2, y2) is input to thedata selector 76. The timing of the input of the extraction image bitmapdata BMD1 to the data selector 76 is controlled by the CPU 20, based onthe sync signal WSYNC and the coordinate data PD. The timing of theinput of the extraction image bitmap data BMD1 is determined by usingcoordinate data PD of the extraction image bitmap data BMD1 to obtainthe input timing of the pixel image data DV1 for the overlay position.Simultaneously with the input of the extraction image bitmap data BMD1,the extraction image bitmap data BMD1 is selected by the selectionsignal SEL. In this way, a selection between image data DV1 andextraction image bitmap data BMD1 can be made with respect to each pixelassigned to the same position in the image.

When the extraction image bitmap data BMD1 is expanded as shown in FIG.7, pixel data of the image data DV1 and extraction image bitmap dataBMD1 corresponding to the same position in the image are inputsimultaneously to the data selector 76. The input pixel data isspecified based on the sync signal WSYNC. Thus, pixel data can beassigned to the same position in the original image by synchronizing thereadout of the extraction image bitmap data BMD1 from the extractionimage memory 24 with the input of the image data DV1 to the videoprocessor 62. Also, the extraction image can be superimposed on theoriginal image by using the coordinate data PD as a basis for supplyingthe selection signal SEL to the data selector 76.

When overlay image data is written to, or read from, the frame memory22, the write controller 70 and read controller 72 generate addressesADD1, ADD2 and control signals CTR1, CTR2, which are supplied to theframe memory 22. Overlay image data is written to the frame memory 22 inaccordance with address ADD1 and control signal CTR1 generated by thewrite controller 70, and read out of the frame memory 22 in accordancewith address ADD2 and control signal CTR2 generated by the readcontroller 72. These addresses and control signals are based on the syncsignals WSYNC and RSYNC.

The writing of overlay image data to the frame memory 22 is synchronizedwith the sync signal WSYNC. The reading of overlay image data from theframe memory 22 is synchronized with the sync signal RSYNC output by theliquid crystal display driver circuit 14 (FIG. 12). The sync signalsWSYNC and RSYNC are not mutually synchronized. However, sync signalsWSYNC and RSYNC can be synchronized.

In this embodiment the overlay image data can be obtained by writingdirectly to the frame memory 22. Overlay image data written to the framememory 22 is read out by the video processor 62.

Overlay image data DDV2 output by the video signal conversion circuit 60(FIG. 12) is supplied to the liquid crystal display driver circuit 14(FIG. 12). Based on this overlay image data DDV2, the liquid crystaldisplay driver circuit 14 displays on the liquid crystal display panel16 the image overlaid with the extraction image. The image displayed onthe liquid crystal display panel 16 is projected onto the projectionscreen 104 by the optical systems 100 and 102.

In the first and second embodiments described in the foregoing, at leasta portion of images input to the projection display apparatus can beextracted as the extraction image internally. It is therefore possibleto extract part of one input image and overlay it on another. This meansit is possible to extract an image from an image signal input from apersonal computer, video recorder or TV and overlay the extracted imageon an input image. Moreover, by using the coordinate data PD, anextraction image can be superimposed at any desired point on the inputimage, and enlarged or reduced.

C. Third Embodiment

Embodiments of a second aspect of the invention are described below.

C-1. Configuration and Operation of the Projection Display Apparatus:

FIG. 15 is a block diagram for schematically illustrating the generalconfiguration of an embodiment of the projection display apparatusaccording to a second aspect of the invention. The projection displayapparatus includes a video signal processing circuit 210, an on-screendisplay (OSD) controller 212, an OSD memory 213, a liquid crystal lightvalve driver circuit 214, a liquid crystal light valve 216, a framememory 222, an extraction image memory 224, a remote control section 28,a CPU 20, an illumination optical system 100 and a projection opticalsystem 102. The video signal processing circuit 210, OSD controller 212,extraction image memory 224, remote control section 28 and CPU 20 areconnected by a bus 1.

The video signal processing circuit 210 is used to performanalog-digital conversion of input analog video signals AV1, write theconverted image data into the frame memory 222 and retrieve image datafrom the frame memory 222. The analog video signal AV1 can be an RGBsignal S1 carrying a computer screen image, or a composite image signalS2 from a video recorder, TV or the like.

FIG. 16 is a block diagram for schematically illustrating theconfiguration of the video signal processing circuit 210. The videosignal processing circuit 210 includes a sync separator 230, an A-Dconversion section 232 and a video processor 234. The functions of thesync separator 230 and A-D conversion section 232 are the same as thoseof the sync separator 30 and A-D conversion section 32 of the firstembodiment (FIG. 2), so further explanation thereof will be omitted.

The video processor 234 is a microprocessor that performs various imageprocessing functions such as controlling the input and output of imagedata and extraction image data to and from the frame memory 222 andextraction image memory 224. Image data DV1 from the A-D conversionsection 232 is input to the video processor 234. Specific image datathat includes extraction image data CPD1 stored in the extraction imagememory 224 and background image data BGD1 generated by the CPU 20 isinput to the video processor 234, via bus 1.

FIG. 17 is a block diagram showing the configuration of the videoprocessor 234. The video processor 234 includes a write controller 270,a read controller 272, an extraction controller 274 and a data selector276. The controllers 270 and 272 have the same functions as thecontrollers 70 and 72 of the first embodiment (FIG. 3), so furtherexplanation thereof will be omitted.

Image data DV1 and specific image data SPD1 that includes extractionimage bitmap data BMD1 stored in the extraction image memory 224 andbackground image data BGD generated by the CPU 20 are input to the dataselector 276, along with a selection signal SEL. There is a dataselector 276 for each of the colors RGB. The selection of the image dataDV1 and specific image data SPD1 is controlled by the selection signalSEL. Which data is selected depends on whether the system is in normaldisplay mode or specific image display mode. These modes are discussedbelow. Based on the selection signal SEL, the data selector 276 selectseither image data DV1 or specific image data SPD1. Thus, according tothe system mode, either one of image data DV1 and specific image dataSPD1 is written into the frame memory 222. When user uses the remotecontroller 29 to select the system mode, the selection signal SEL isgenerated by the CPU 20.

The writing of image data to the frame memory 222 is synchronized by thesync signal WSYNC when the data to be written to the memory 222 is inputimage data DV1. When the data to be written to the memory 222 isspecific image data SPD1, the write operation is controlled by signalssupplied to the write controller 270 by the CPU 20. The retrieval ofimage data from the frame memory 222 and the downstream processing ofimage data DV2 output by the video processor 234 are synchronized by thesync signal RSYNC output by the liquid crystal display driver circuit214 (FIG. 15), discussed below, which is optimized for driving theliquid crystal light valve 216. The sync signal RSYNC is produced by async signal generator (not shown) in the video processor 234. The syncsignals WSYNC and RSYNC are not mutually synchronized. However, syncsignals WSYNC and RSYNC can be used synchronized. The sync signalgenerator does not have to be provided in the video processor 234, andcan instead be provided in the liquid crystal light valve driver circuit214, for example, or can be configured as an independent component.

When image data that has been written to the frame memory 222 is readout, the function of the extraction controller 274 is to extract aspecified portion of the image data. The extraction controller 274 alsoenlarges or reduces the extraction image data in accordance with theenlarging/reducing factor that has been set. Another function of theextraction controller 274 is to write the extraction image data CPD1 tothe extraction image memory 224 via the bus 1. The portion of the imagedata to be extracted (extraction area) can be specified using the remotecontroller 29. When the extraction area has been specified, the CPU 20outputs an extraction address SADD corresponding to the extractionportion. Based on the extraction address SADD and address ADD2 read fromthe read controller 272, the extraction controller 274 extracts theimage data of the specified portion. This make it possible to extractonly the specified portion of the image data.

Image data DV1 or specific image data SPD1 stored in the frame memory222 is read out of the frame memory and output from the video processor234 as image data DV2. The readout operation is synchronized by the syncsignal RSYNC.

The extraction image memory 224 shown in FIG. 15 is for storingextraction image data CPD1 extracted by the extraction controller 274 ofthe video processor 234 (FIG. 17). Extraction image data CPD1 is storedin the extraction image memory 224 in a specific format. There are noparticular limitations on the specific format other than it be decidedbeforehand. For example, it can be compressed data, or bitmap data. Ifthe extraction image data CPD1 is specified as compressed data, it iswritten into the extraction image memory 224 after being compressed bythe CPU 20 or the extraction controller 274. Similarly, when the data isread out of the extraction image memory 224, it is expanded by the CPU20 or the extraction controller 274.

FIG. 18 is a diagram illustrating the extraction image memory 224. Theextraction image memory 224 stores the data for one extraction image.The stored data includes an information ID denoting the content of theextraction image data, and extraction image data CPD1. The extractionimage memory 224 is not limited to storing one set of data, and mayinstead be used to store multiple sets.

The OSD controller 212 shown in FIG. 15 generates OSD image datarepresenting pointer images and menu screens for controlling thefunctions of each part of the projection display apparatus in accordancewith commands received from the remote controller 29 via the remotecontrol section 28. The OSD memory 213 contains pointer image data andgraphics and font data for the menu screens, stored in a specificformat. To display the menu screens and pointers images, the OSDcontroller 212 reads out the corresponding data from the OSD memory 213and generates OSD image data. The OSD controller 212 combines this OSDimage data with image data DV2 output by the video signal processingcircuit 210. The image data DV2 and OSD image data could also becombined by providing the OSD controller 212 with a selector.Alternatively, it could be done by providing two multipliers thatmultiple the image data DV2 and OSD image data by a fixed factor, and anadder that adds the results of the multiplications. Images forspecifying the extraction area (extraction area specifying image) aregenerated by the OSD controller 212.

Image data DV3 output by the OSD controller 212 is input to the liquidcrystal light valve driver circuit 214. Based on the image data DV3, theillumination light from the illumination optical system 100 is modulatedby the liquid crystal light valve 216, and the modulated light isprojected onto the screen 104 by the projection optical system 102 todisplay the image. The liquid crystal light valve 216 corresponds to theelectro-optical device of the second aspect of the invention. The liquidcrystal light valve driver circuit 214 corresponds to the image displaysignal generator of the second aspect of the invention.

Here, the term projection optical system is used in a broad sense thatalso encompasses the illumination optical system. The liquid crystallight valve driver circuit 214 can be formed on the substrate of theliquid crystal light valve 216 as the electro-optical device,integrating the two components.

The image data DV3 output by the OSD controller 212 can be enlarged orreduced by an enlarging/reducing circuit (not shown) provided betweenthe OSD controller 212 and the liquid crystal light valve driver circuit214.

The projection display apparatus is controlled by the remote controlsection 28, based on commands from the remote controller 29 (FIG. 15).The remote control section 28 controls mainly processing related toextraction images. In accordance with commands received from the remotecontroller 29, this includes specifying the extraction portion of theimage data, and whether extraction images are displayed or not.

The functions of the video signal processing circuit 210, OSD controller212 and remote control section 28 can be implemented by a computerprogram instead of in hardware.

When the remote controller 29 is used to select the normal image displaymode, digital image data DV1 representing analog image signals AV1externally input to the video signal processing circuit 210 is stored inthe frame memory 222 and the images can be displayed on the screen 104.FIG. 19 is a diagram for explaining externally input images displayed onthe projection screen 104. When the remote controller 29 is used toselect the specific image display mode, background image data BGD1generated by the CPU 20 and extraction image data CPD1 stored in theextraction image memory 224 are stored in the frame memory 222 asspecific image data SPD1 and the specific images represented by the dataSPD1 can be displayed on the screen 104. FIG. 20 is a diagram forexplaining the projection screen display of a specific image representedby the specific image data SPD1 that includes background image data BGD1and extraction image data CPD1 stored in extraction image memory 224.

When the user selects the specific image display mode, an extractionimage can be selected from among those stored in the extraction imagememory 224 and displayed as a specific image. It is also possible toselect multiple extraction images from among those stored in theextraction image memory 224 and have them displayed repeatedly in order.FIGS. 21( a)–(c) are diagrams for explaining the display on theprojection screen 104 of sequentially selected extraction imagesrepresented by extraction image data CPD1 (A), CPD1 (B) and CPD1 (C).

During question and answer sessions in a presentation or when a shorttime is needed before a new set of images can be displayed, thepresentation can be enhanced by displaying specific images in the formof corporate logos and product images and the like instead ofpresentation images.

The extraction image data CPD1 stored in the memory 224 can be extractedas explained below.

C-2. Extracting Images:

FIGS. 22 to 27 are diagrams illustrating the procedure for cutting awayfrom an image being input to the projection display apparatus, to anextraction image (a user logo image). FIGS. 22 to 27 shown displayimages on the projection screen 104.

The remote controller 29 has a menu key (not shown). When the menu keyis pressed, the OSD controller 212 (FIG. 15) displays a menu screen.Selecting the menu entry “Extraction image setting” and pressing theenter key on the remote controller 29 initiates the extraction imagesetting mode. Below, the term “select” will be used to mean using theremote controller 29 to select a menu item such as letters and areas andpressing the enter key on the remote controller 29. When the extractionimage setting mode starts, the writing of data to the frame memory 222is stopped. This stop can be done according to starting the extractionimage setting mode. A user can use the selection of this mode by usingremote controller 29 as a way of stopping a display of such as movingimages.

When the writing of data to the frame memory 222 stops, the image in theframe memory 222 at that point is displayed on the screen, as shown inFIG. 22. Also, the extraction image setting screen is displayed by theOSD controller 212, showing the question “Use part of this image as anextraction image?” It is decided whether or not to extract image frompresent displayed image. Extracted image is referred to as extractiontarget image. If “No” is selected, the extraction image setting mode isterminated and the menu screen reappears. If “Yes” is selected, the OSDcontroller 212 displays a selecting frame WF of a preset size forselecting the extraction image, as shown in FIG. 23. The selecting frameWF comprises two black outlines separated by a white space. This makesthe selecting frame WF readily visible on the images. Thus, user caneasily select a extraction area. If required, a system configuration canbe used that allows the size of the frame to be set by the user. On theremote controller 29, a pointing device, such as an arrow-key device, isused to position the selecting frame WF and select the part to beextracted on the extraction target image.

As shown in FIG. 24, when user selects the part of the extraction targetimage, the selected image (referred to as selected extraction image)SCPD is then displayed in the center of the screen. A black image isused to mask portions other than the selected extraction image SCPD. TheOSD controller 212 then displays the question “Use this image?” on theextraction image setting screen. It is decided whether or not to use thepresent image. If “No” is selected, the extraction image setting mode isterminated and the menu screen reappears. If “Yes” is selected, the OSDcontroller 212 displays “Please set display magnification,” shown inFIG. 25.

When one of the magnifications displayed on the extraction image settingscreen is chosen, the selected extraction image SCPD is displayed atthat magnification. If a different magnification is then chosen, theimage will be displayed at the new magnification. This enables users totry different settings before making a final selection. Desiredmagnification is set by pressing the enter key. The system can insteadbe configured to accept any desired magnification setting.

When the extraction image and magnification have been selected, the OSDcontroller 212 displays “Save this image?” on the extraction imagesetting screen, as shown in FIG. 26. It is decided whether or not tosave the image data representing this image in the extraction imagememory 224 (FIG. 15) as extraction image data CPD1. If “No” is selected,the extraction image setting mode is terminated and the menu screenreappears. If “Yes” is selected the extraction image data CPD1 is savedin the extraction image memory 224 (FIG. 15) and the message “Theextraction image has been saved” is displayed (FIG. 27). During settingabove, menu screen reappears by pressing the menu key.

This procedure enables a user to readily select a desired extractiontarget image and extract a desired image by following the extractionimage setting screens. Also, the image can be saved in the extractionimage memory 224 with a chosen condition (magnification), which can bechecked before final selection.

The video processor 234, OSD controller 212, remote control section 28and CPU 20 of this embodiment correspond to the image extraction sectionand specific image display control section according to the secondaspect of the invention.

D. Fourth Embodiment:

FIG. 28 is a block diagram for schematically illustrating the generalconfiguration of an embodiment of the projection display apparatusaccording to second and third aspects of the invention. Other than theinclusion of an operating condition judging section 226, this projectiondisplay apparatus has the same configuration as that of the thirdembodiment, so further explanation thereof will be omitted.

FIG. 29 is a block diagram showing the configuration of the operatingcondition judging section 226. The operating condition judging sectionincludes an image signal detector 242, a system start detector 244 and ajudging section 246. The image signal detector 242 receives the syncsignal WSYNC included in the image signal and detects whether an imagesignal is being input to the projection display apparatus. The systemstart detector 244 receives a power supply voltage Vcc and detectswhether the projection display apparatus is on and can display an image.Based on the detection signals D1 and D2 signifying detection by theimage signal detector 242 and system start detector 244, the judgingsection 246 judges whether an externally input image can be displayed.

FIGS. 30( a)–(e) are time charts of the operation of the operatingcondition judging section 226. FIG. 30 (a) shows the power supplyvoltage Vcc, FIG. 30 (b) shows start detection signal D2 output from thesystem start detector 244, FIG. 30 (c) shows the sync signal WSYNCincluded in image signals input to the projection display apparatus,FIG. 30 (d) shows detection signal D1 output from the image signaldetector 242, and FIG. 30 (e) shows operating condition judging signalSPDMODE.

When the supply voltage Vcc is high enough for the projection displayapparatus to start operating, after a prescribed interval T2 the startdetection signal D2 changes from Low to High. Once the projectiondisplay apparatus is provided with a supply voltage, it is ready todisplay specific images in a relatively short time. However, some timeis required as a stabilization period before externally input images canbe displayed, to allow such as sync clocks to be generated on whichinternal circuits are operated. The period T2 represents thisstabilization period. When the start detection signal D2 is Low itsignifies that the system is not yet display-operational. At this time,the operating condition judging signal SPDMODE also is Low, signifyingthat the system is in the specific image display mode in which specificimages are displayed. When the start detection signal D2 goes High,signal SPDMODE also goes High, signifying the system is in the normaldisplay mode in which input images are displayed.

The image signal detector 242 detects whether the sync signal WSYNC isbeing input at prescribed intervals Tc as shown in FIG. 30( c). When thepulse signal is being input at the prescribed intervals Tc, syncdetection signal D1 goes High as shown in FIG. 30( d). When it isdetected that pulse signal is not being input at the intervals Tc, aftera prescribed period Ti the sync detection signal D1 goes Low. Theprescribed period T1 represents a detection margin. When detectionsignal D1 is Low, operating condition judging signal SPDMODE changes toLow, and specific images can be displayed.

Thus, in this embodiment, after the projection display apparatus hasbeen started the operating condition judging section 226 detects whetherthe system state enables images to be displayed, and also detectswhether an image signal is being received. The system can thenautomatically switch between normal display mode in which input imagesare displayed, and specific image display mode in which specific images(explained in third embodiment) are displayed.

The operating condition judging section 226 of this embodimentcorresponds to the operating condition judging section of the second andthird aspects of the invention. Also, the video processor 234, OSDcontroller 212 and CPU 20 correspond to the image extraction section andspecific image display control section of the second and third aspects.

Although the image signal detector 242 uses the sync signal WSYNC todetect whether image signals are being input, this is not limitative,and various detection methods can be used. For example, color signals orluminance signals could be used, with an image signal staying at blacklevel for a certain time signifying that an image signal is not beingreceived.

The present invention is in no way limited to the details of theexamples and embodiments described in the foregoing but various changesand modifications may be made without departing from the scope. Forexample, the following modifications are also possible.

The first to fourth embodiments have been described using a projectiondisplay apparatus as an example, but this is not limitative, with theinvention being applicable to various other types of image displayapparatus.

In the case of the first embodiment, the data selector 76 shown in FIG.14 could be used to superimpose the extraction images instead of the twomultipliers 40 and 42 and the adder 44 used in the extraction imageoverlay circuit 12 (FIG. 5). This would enable the extraction images tobe given a filled-in effect equivalent to the effect obtained when thecoefficients (k1, k2) of the multipliers 40, 42 are set at (1, 0) or (0,1).

With respect again to the multipliers 40 and 42 and the adder 44 used bythe circuit 12 to superimpose extraction images in the first embodiment,if the coefficients k1 and k2 are both set at ½ to provide transparentimages, the multipliers 40 and 42 will not be needed. Instead, the sameeffect can be obtained by effecting a bit shift in the adder 44 toremove the low-order bit from the data that is added.

In the second embodiment, the multipliers and adder shown in FIG. 5 canbe used instead of the data selector 76 (FIG. 14) to superimposeextraction images. This would enable transparent as well as filled-inoverlay effects to be provided.

In the first and second embodiments, while memory capacity equivalent toone frame of image data is allocated for expanding extraction images, asshown in FIG. 7, the same effect can be obtained by using flags in placeof coordinate data PD. For example, the pixel data of an extractiongraphic in the extraction bitmap data could be provided with a one-bitflag that could be used to determine the presence or absence of thegraphic. Depending on the presence or absence of the flag, an adjustmentcould be made to the coefficients k1, k2 of the multipliers 40, 42 (FIG.5), in the case of the first embodiment, or to the selection by the dataselector 76 (FIG. 14), in the case of the second embodiment. In thisway, the same effect could be obtained as when coordinate data is used.

In the first and second embodiments, extraction image bitmap data BMD1is expanded and stored in the extraction image bitmap memory 26 orextraction image memory 24, but this expansion is not limited to thememories 26 and 24 and may be effected in other storage areas preparedfor the purpose.

In the first and second embodiments, the only extraction images storedin the extraction image memory 24 are those extracted by the extractioncontroller 74, but this is not limitative. Instead, images producedusing other devices, such as scanned images and images produced on acomputer, can also be stored in the extraction image memory 24. Doingthis makes it possible to overlay original images with other images inaddition to images extracted by the projection display apparatus.

In the first and second embodiments, moreover, images to be superimposedon input images are maintained in the extraction image memory 24, butthe invention is not limited to this configuration. Instead, bitmap dataof graphics drawn using the remote controller 29 could be writtendirectly to the extraction image bitmap memory 26, enabling drawn imagesto be used as overlays. This would make it possible for a user using adrawing program to overlay an extraction image of a desired shape, suchas a free curve or the like, specified with the remote control 29.

The third and fourth embodiments have been described with reference towriting specific image data SPD1 into the frame memory 222 to displayspecific images, but the invention is not limited to this. Instead, forexample, the specific image data SPD1 can be written to the OSD memory213 and displayed as OSD images by the OSD controller 212.

The third embodiment, has been described, using as an example, employingthe image extraction section according to the second aspect of theinvention to display specific images that include arbitrarily extractedimages. However, this is not limitative. A projection display apparatusconfiguration can be used that does not include an image extractionsection, with specific images supplied by a computer or from recordingmedia read by a reading apparatus being displayed.

The operating conditions described with reference to the fourthembodiment are not limited to the operational status of the projectiondisplay apparatus or to whether image signals are being received.Various other conditions can be set and associated detection circuitsincluded in the operating condition judging section.

In the first and second embodiments a liquid crystal display panel 16 isused as the light modulation unit of the projection display apparatus,but the invention is not limited to this and can use as the lightmodulation unit any means that is able to modify luminance based on theimage data. For example, a light modulation unit can be used thatutilizes light reflected by a pixel array of mirror elements, or a CRTor plasma display panel or the like. Note that, usually, a CRT or plasmadisplay panel are not called light modulation unit.

Similarly, the electro-optical device used in the third and fourthembodiments is not limited to the liquid crystal light valve 216.Various other devices that emit light according to image signal areusable as electro-optical device, such as a DMD (digital micromirrordevice, trademark of Texas Instruments Inc.), CRT or plasma displaypanel.

In the described embodiments, part of the configuration implemented byhardware can instead be implemented by software and, conversely, part ofthe configuration implemented by software can instead by implemented byhardware.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a variety of image displayapparatuses. The projection display apparatuses of the present inventionis applicable to projecting onto a screen images input by such as acomputer and a video recorder.

1. A projection display apparatus that projects images onto a screenresponsive to given image data, comprising: an image extraction sectionthat extracts at least a portion of given first image data as anextraction image; an extraction image memory that stores extractionimage data representing the extraction image; an image overlay sectionthat generates overlaid image data by superimposing the extraction imageon original image represented by given second image data and providesthe overlaid image data as an electrical signal at an image overlaysection output; a light modulation unit that is connected to the imageoverlay section output and driven pixel by pixel in response to theoverlaid image data contained in the electrical signal received from theimage overlay section output; and an optical system for projecting ontothe screen the overlaid image obtained by the light modulation unit,wherein the extraction image memory stores a plurality of extractionimage data representing a plurality of extraction images, and the imageoverlay section superimposes at least one extraction image selectedamong the plurality of extraction images at each specified position onthe original image, wherein the image overlay section comprises, asynthesizer section that generates the overlaid image data bysynthesizing the given second image data and the extraction image dataread out from the extraction image memory, and a frame memory thatstores the overlaid image data, the frame memory having at least amemory area corresponding to all the pixels of the light modulationunit, the overlaid image data read out of the frame memory beingsupplied to the light modulation unit, and wherein the synthesizersection comprises, a multiplier section that multiplies the second imagedata and the extraction image data by respective coefficients on a pixelby pixel basis, and an adder section that adds the multiplied secondimage data and the extraction image data on a pixel by pixel basis.
 2. Aprojection display apparatus according to claim 1, wherein the imageextraction section can arbitrarily set the portion to be extracted fromthe first image data.
 3. A projection display apparatus according toclaim 1 or 2 wherein the image overlay section superimposes theextraction image at a desired position on the original image.
 4. Aprojection display apparatus according to claim 1, wherein thesynthesizer section comprises a data selector that selects one of thesecond image data and the extraction image data pixel by pixel, toproduce the overlaid image data.
 5. A projection display apparatus thatprojects images onto a screen responsive to given image data,comprising: an image extraction section that extracts at least a portionof given first image data as an extraction image; an extraction imagememory that stores extraction image data representing the extractionimage; an image overlay section that generates overlaid image data bysuperimposing the extraction image on original image represented bygiven second image data and provides the overlaid image data as anelectrical signal at an image overlay section output; a light modulationunit that is connected to the image overlay section output and drivenpixel by pixel in response to the overlaid image data contained in theelectrical signal received from the image overlay section output; and anoptical system for projecting onto the screen the overlaid imageobtained by the light modulation unit, wherein the extraction imagememory stores a plurality of extraction image data representing aplurality of extraction images, and the image overlay sectionsuperimposes at least one extraction image selected among the pluralityof extraction images at each specified position on the original image,wherein the image overlay section comprises, a frame memory that storesthe given second image data, the frame memory having at least a memoryarea corresponding to all the pixels of the light modulation unit, and asynthesizer section that generates the overlaid image data bysynthesizing the second image data read out from the frame memory andthe extraction image data read out from the extraction image memory, theoverlaid image data synthesized by the synthesizer section beingsupplied to the light modulation unit, and wherein the synthesizersection comprises, a multiplier section that multiplies the second imagedata and the extraction image data by respective coefficients on a pixelby pixel basis, and an adder section that adds the multiplied secondimage data and the extraction image data on a pixel by pixel basis.
 6. Aprojection display apparatus according to claim 1 or claim 5, whereinthe synthesizer section comprises a coefficient setting section thatcontrols the coefficients in the multiplier section to change asynthesis ratio between the second image data and the extraction imagedata, thereby adjusting a degree of transparency of the extraction imagesuperimposed on the original image.
 7. An projection display apparatusaccording to claim 6, wherein the coefficient setting section changesthe coefficients in the multiplier section with time to change thesynthesis ratio between the second image data and the extraction imagedata, thereby changing the degree of transparency of the extractionimage superimposed on the original image with time.
 8. A method ofdisplaying images using a projection display apparatus having a lightmodulation unit to display an image based on image data given to theprojection display apparatus by projecting the image on a screen,comprising the steps of: extracting at least a portion of given firstimage data as an extraction image; preparing extraction image datarepresenting the extraction image; generating overlaid image data bysuperimposing the extraction image on an original image represented bygiven second image data and providing the overlaid image data as anoverlaid image electrical signal; driving a light modulation unitresponsive to the overlaid image electrical signal on a pixel by pixelbasis; and projecting overlaid images obtained by the light modulationunit onto a screen, wherein an extraction image memory is provided tostore a plurality of extraction image data representing a plurality ofextraction images, and the step of generating overlaid image data bysuperimposing the extraction image on an original image is performed bysuperimposing at least one extraction image selected among the pluralityof extraction images at each specified position on the original image,wherein the step of generating overlaid image data comprises, generatingthe overlaid image data by synthesizing the given second image data andthe extraction image data read out from the extraction image memory, andstoring the overlaid image data in a frame memory, the frame memoryhaving at least a memory area corresponding to all the pixels of thelight modulation unit, the overlaid image data read out of the framememory being supplied to the light modulation unit, and wherein the stepof generating the overlaid image data by synthesizing the given secondimage data and the extraction image data read out from the extractionimage memory comprises, multiplying the second image data and theextraction image data by respective coefficients on a pixel by pixelbasis, and adding the multiplied second image data and the extractionimage data on a pixel by pixel basis.